imageresponseencoder.java

mina是以Java实现的一个开源的网络程序框架

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 *   Licensed to the Apache Software Foundation (ASF) under one
 *   or more contributor license agreements.  See the NOTICE file
 *   distributed with this work for additional information
 *   regarding copyright ownership.  The ASF licenses this file
 *   to you under the Apache License, Version 2.0 (the
 *   "License"); you may not use this file except in compliance
 *   with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 *   Unless required by applicable law or agreed to in writing,
 *   software distributed under the License is distributed on an
 *   "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 *   KIND, either express or implied.  See the License for the
 *   specific language governing permissions and limitations
 *   under the License.
 *
 */
package org.apache.mina.example.imagine.step1.codec;

import org.apache.mina.filter.codec.ProtocolEncoderOutput;
import org.apache.mina.filter.codec.ProtocolEncoderAdapter;
import org.apache.mina.core.buffer.IoBuffer;
import org.apache.mina.core.session.IoSession;
import org.apache.mina.example.imagine.step1.ImageResponse;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;

/**
 * an encoder for {@link ImageResponse} objects 
 *
 * @author The Apache MINA Project ([e-mail])
 * @version $Rev$, $Date$
 */
public class ImageResponseEncoder extends ProtocolEncoderAdapter {

    public void encode(IoSession session, Object message, ProtocolEncoderOutput out) throws Exception {
        ImageResponse imageResponse = (ImageResponse) message;
        byte[] bytes1 = getBytes(imageResponse.getImage1());
        byte[] bytes2 = getBytes(imageResponse.getImage2());
        int capacity = bytes1.length + bytes2.length + 8;
        IoBuffer buffer = IoBuffer.allocate(capacity, false);
        buffer.putInt(bytes1.length);
        buffer.put(bytes1);
        buffer.putInt(bytes2.length);
        buffer.put(bytes2);
        buffer.flip();
        out.write(buffer);
    }

    private byte[] getBytes(BufferedImage image) throws IOException {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        ImageIO.write(image, "PNG", baos);
        return baos.toByteArray();
    }
}